Electric meter.



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2 SHEETS-SHEET l.

IrwOerwtOr am H. Pratt PATBNTED Nov. e, 190e.

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` wim @y W H. PRATT BLBUTR-IC METER. PPLIUATIUN FILED APB. 2o. 1904.

No. 835,321. PATENTED NOV. 6, 196. W. H. PRATT.

ELECTRIC METER.

APPLICATION FILED APE. 20. 1904.

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lfnoerwbcm- @Dilliahnl H UNITED sTApns PATENT OFFICE.

l/VILLIAM H. PRATT, OF LYNN` MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

ELECTRIC METER'.`

Specification of Letters Patent.

Patented Nov. fr, 1906.

To a/ZZ whom it may concern:

Be it known thatI, WILLIAM H. PRATT, a

citizen of the United States, residing at Lynn, in the county of Essexand State of Massachusetts, have invented certain new and useful Imrovements in ElectricMeters, of which the fo owing is a specification.

My invention relates to alternating-current induction-meters; and itsobject is to provide a wattmeter of "simple and compact constructionwhich shall o crate emciently and accurately on varying oads and powerfactors.

One feature of my invention consists in the novel arrangement of themagnetic circuit whereby a high torque and roper phase displacement aresecured for allloads and power factors.

Another feature of my invention consists in providing means forcounterbalancing the starting-frlction, whereby the adjustment forcompensating for friction does not alter the phase displacements of themagnetic circuit.

Another feature of my invention consists in a novel connection betweenthe moving y element of the meter and ythe recording mechanism, wherebyadisplacement of one relative to the other does not introduce errors inthe record by changing the friction losses.

Other features of my invention will appear from the followingspecification and from the' accompanying drawmgs, in which- .Flgure 1shows a front view in elevation of a meter constructed in accordancewith my invention with. the front .cover cut. away.A Fig.' 2 shows arear view in elevation of theA same with the backof the cover cut away.

.` 2F ig. 3 shows a side elevation of the same 1n cross-section, thelines ,1, 1 and 2 2 in this iig-V ure indicating the planes in which theviews of Figs. 1 and 2, respectively, `are 'taken'. Fig. 4 showsdagrammatically the `magnetic circuit ofthe meter and Figs. 5l and showdiagr-ammatically't e' relative positions and connections of the coilsof the meter.

Referring first to Fig. BVA' represents the front Vcover of the meter,which is-secured to the back cover A by. the bolts a. 'The bolts a are'threaded at both ends, one end screwin'giinto .the studs c of thebackbcover A and the other end receiving the nut c". B repre- 'sents theframe, to which all working parts of the meterare attached. Frame Bisbolted.

.by reference to Fig.`4.

the movable armature D, which consists of the usual conducting-disk andthe stationary ma netic circuit, with its energizing-coils. Dis D iscarried by shaft c, which 1s supported in the usual manner on'eWeLbeaTings carried by the frame B. T e 'stationary magnetic circuitconsists of-two laminated cores C and C', secured to frame B by thebolts c. The arrangement of the magnetic circuit and its coils will bestbe understood In this figure core C is shown with three aralel membersconnected at the top wit the potential-coil P, mounted on the centralmember. has its extremities extending intoclose roximit with the` threemembers orV o lcs oFcore C,A t ereby forming withcore` a nearl 'closedmagnetic circuitfor potential-coil .whereby current in coil P 1s lagged'in the4 manner well understood in the art'.` Oore C is provided withtwo poles facing the central e of core C. On these poles are placed theseries or current coils S.1 V ,A

The disk, which isnot shown in Fig. 4, is disposed between thepoles onwhich coils S are placed and the centrall pole of core .C. The' leakageflux of'coilP, which does not ass through the nearly-closedcircuitoffered Core VC by the extremities of core C', passes fromthe centralpole of core'C through the-diskfc0 the oles on' '.which are mountedthecoils S." he coilsS S are oppositely Wound and profduce fluxes whichwith thei'u'x from the central pole f core C produce a shiftingesultantixj'and consequent rotation'of the disk, in aj manner well understoodinV the; art. i The short-circuitedcoil L is mounted oir-theniids .dlepole .of coreC andis traversed-bythe ffiux that passesthrough the.diskto theSpoles-ef the .series coils',- andfthereby produesthenir'ietiy-degree displacement yof the potential.-

flux om that ofthe series coils in the'nlannerunderstoodlin theart.; 'Y

It will b'e eeen from the drawings the above'description thatfthefs'eries coils Q have e nearly-closed magnetic circuit und acup tothe terminal cordingly exert e strong torque. The errangement of thecores (l and C is compact and well adapted tor producing the properphase displacement ot the fluxes.

In order to com icnsute for the sluiting friction, I rovide the closedcircuit it, which is suspenc ed directly above the disk und which may bemoved ho'rizoiiititlly townrii either series coil. When this closedcircuit is in its central position, syn'nnetrically disosed withreference to the uiugzjnctic circuit of the shunt-coil, it luis noelli-.ct upon the starting torque of the` meter. ll it is univr-.d ineither direction from its ccntrui position se thatO it isassynnuetricclly disposed with rei! ererce to'the seid magnetic circuit`torque is pro uced thereby in one direction or the other, sind the stm'lingd'rictioii is thereby compensated for. Moreover, since there uretwo series coils and sincr` the closed circuit E by its movementincliulcf. nuire ol' the fluir from one coil es it includes less inn;tbc other, the bese displacement ci' tur luxrs is not altere( by itsadjustment. iConseouenlly I have rovided e simple means for compete;eating or sturtinghfriction withoutwei-ying the phcse displacement, undti'lcreby im'uuir-4 ing the accuracy of the meter. The cllosed circuitE, which is formed :is e. simple rec-- tangular loo i, es shown in Fig.5,` is sup-v ported from ironie B by the clumpingscrews e, as shown inFigs. 1 and 3. The clernpingscrews c ass thrruigb slots in lugs on theend of plete as shown in Figs. i and P, and permit the member E to bemoved horizontally by Ineens of the lever F, which is pivotcd :rtf andengages one of the upturned lugs of member c'.

The drg-megnets M ere shown in Figs. l and 8 and are supported fromframe B, es in diceted in the drawings. The dial-plete H is supported onstuds h, carried by freine B, es shown in Fig. 3. The connection betweenthe disk D und the mechanism for the die]u plate is as follows: Shaft dcarries e., worm t, which en ages u geur-wheel mounted on shaft y', wich is supported from traine B 1n close roximity to the upper support ofshaft The maintenance of perfect elinement between Worm 'i and shaft isthereby assured. Shaft carries an arm k, which es it revolves engages spin m, carried by shaft n, Which is connected to the gear-trein. (Notshown.) Arm 7c drives pin 1ny by simply pressing against it, therebyforming e loose yet positive connection between. shaft j and shaft fn.Any displacement of the dial H with its geentrain relative to disk-shaftd can produceA no binding in any part of the transmitting mechanism, undconsequently can introduce no frietional error.

Fig. 5 shows diegrammetieelly the errangement of the coils and theirconnections. The lagging coil L has its terminals brought l l l i l illi l l l l l ilutc l in order that its elfcct muy be vitrier by thcinsertion of rcsistuncc in its circuit, if required. Fig. 6 shows umodified arrangement in which two sets of series colis crc used. Such:tu m*- rungcment is suited l'or measurement of cncrgy on u three-Wiresystem. No further explanation is believed nm'cssury.

Vhiie lV have shown n complete embodiment of my invention, it will beunderstood that the construction und arrangement of parte` muy begreatly clnmgcd without departing from the spirit of my invention.li`iirthermmc, l have shown und described severe! novel. tentures which.l desire to claim whether' used together or singly.

Acciirdingly i do not desire to limit myself to the purticulerconstructibn. end arrangement of purts here shown, since changes 'whichdo not deport from the spirit'of my in vention und which crc `within thescope of the nl peiided claims will be obvious to those skilled in thecrt What i cluim ns new, und desire to secure by Letters Patent of theUnited States, is

1. ln an electric meter, a magnetic core comprising three parallelmembers joined et one end, e potentiel-coil mounted on the centrelmember thereof, e rotatable disk mounted. opposite seid central member,le second core extending into close proximity` to said members andforming therewith a neerl closed magnetic circuit for seid potentialcoilindependent of seid disk, end a series winding arranged. opposite sari dcentral member on the other side of seid disk.

2. In an electric meter, e magnetic core comprisingr three parallelmembers joined et one end, the central member extending beyond the othertwo, a. potential-coil `mounted on seid central member, a, second coreeX- tending into close proximity to said members end forming therewith anearly-closed ma netic circuit tor seid potentiakcoil, a closedcircuitedcoil. .mounted on the extension'of said. central member, e seriesWinding disosed o )positie the end of said central member, en( arotatable disk mounted between said central member and seid serieswinding.

3. In en electric meter, e magnetic core comprising three parallelmembers joined'at one end, u potential-'coil mounted on the centrolmember thereof, a rotatable disk mounted opposite said central member,a, second core extending into close proximity to said members andforming therewith' a nearlyclosed magnetic circuit `for seidpotentialcoil independent of said disk, an e series windingmounted onsaid second core opposite seid central member.

4. In en electric meter, s` magnetic core comprising three parallelmembers joined at one end, the central member extending beyond the othertwo, a potentiateoilmouuted on said central member, a. secondcore ex-XCC tending into close proximity to said members and forming therewith anearly-closed mag netic circuit for said potential-coil, aclosedcircuited. coil mounted on the extension ol said central member, aseries winding mounted on said second core opposite said. centralmember, and a rotatable disk mounted be tween said central member andsaid series winding.

5. In an electric meter, a magnetic core comprising three parallelmembers joined at one end, a potential-coil mounted on the cenH tralmember thereof, a rotatable disk mounted opposite said central member, asecond core extending into close proximity to said members and formingtherewith a nearlyclosed magnetic circuit for said potential-coilindependent of said disk and having two olar rejections opposite to thecentral memlier o the first core, and series coils mounted on said polarrejections.

6. In an e ectric meter, a magnetic core comprising three parallelmembers joined at one end, the central member being longer than theother two, a potential-coil mounted on said central member, a secondcore extending into close proximity to said members and formingtherewith a nearly-closed magnetic circuit for said potential-coil andhavin two polar projections opV ositeto said centra member, and seriescoi s mounted on said polar extensions.

7. In an electric meter, a magnetic core comprising three parallelmembers joined at one end, the central member rextending beyond theother two, a' potential-'coil mounted on said central member, a secondcore' extending into close proximity to said members and formingtherewith a nearly-closed magnetic circuit for said potential-coil andhaving two polar projections o posite to said central member, serieslcoi s mounted on said polar projections, and a' closed-circuited coilmounted on the extension of said central member.

S. In an electric meter, a magnetic core having polar projections, apotentialcoil mounted thereon, a rotatable disk opposite said polarprojections, a second core extending into close proximity to the firstcore and forming therewith a nearly-closed magnetic circuit for saidpotential-coil independent of said disk and having polar projections oposite to a pole on the first core energize by said potential-coil, andseries coils mounted on sald last-mentioned polar projections.

9. In an electric meter, a magnetic core, a potential-coil mountedthereon, a second core extending into close'proximity to the first coreand forming therewith a nearly-closed dispose between said. two polesand the first-named pole and adjustable relatively thereto.

11. In an electric meter, a potential-coil, a pole energlzed thereby,two serles coils, two poles energized thereby and facimy the hrstnamedpole, and a short-circuitei conduct-- ing member disposed between saidtwo poles and the Alirst-named pole and adjustable in a plane perendicular to the llux passing between sai poles.

12.v In an electric meter, a potential-coil, a pole energized thereby,two series coils, two poles energized thereby and facing the firstAnamed pole, and a short-circuitcd conducting member embracing'aportion-of the flux 'from each series pole and ad'ustable to varysimultaneously andoppositely the portion of the iiux from each seriespole embracedy thereb i.

13. In an electric meter, a poteiitial-coih a pole energized thereby,two series coils, two poles ener ized thereby and facin the {irstL namedpo e, and a short-circuiter conductingmember embracing a portion of thelinx from each series pole and adjustable toward either series pole in aplane perpendicular to the flux.

14. In an electric meter, a rotatable disk,

magnetic poles on opposite sides of said disk, a short-cncultedconducting member disposed between said poles andadjustablein a planeparallel to the plane of the disk, and a ivoted adjusting-lever engagingsaid memer.

15. In an electric meter, a rotatable disk, :magnetic poles on oppositesides of said disk, a s posed between said poles and adjustable in aplane parallel to the plane of the disk, and4 a pivotedadjusting-leverengaging said memer and movable in a plane perpendicular to the disk.

In witnesswhereof I have hereunto set my hand this 18th day ofApril,1904.

WILLIAM H.l PRATT.

Witnesses: l

DUGALD Meli. MoKILLor, HENRY O. Wns'rnNDAnr.

ort-c1rcuited conducting member dis-Y TOO IOC

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